Mica undercutter



Dec. 8, 1964 F. LoBAsl-l ETAL MICA UNDERCUTTER '7 Sheets-Sheet 1 Filed Oct. 25, 1962 INVENTORJ FLaYo oBAsH MEL v/NJJTRAUB Y LEQNARDJ.' NuTJa/v L W w F/Gl Dec. 8, 1964 F. I OBAsH ETAL 3,160,070

MICA UNDERCUTTER Filed Oct. 25, 1962 7 Sheets-Sheet 2 Q INVENToRs Floro 05A 6H MELv//v JJTR/u/e ATTORNEY:

Dec. 8, 1964 F. LoBAsH ETAL MICA UNDERCUTTER 7 Sheets-Sheet 4 immun Filed Oct. 25, 1962 0 u @www OHAU N TsRN R mwk. m we? l 0J D NR own Y L N nM/ Dec. 8, 1964 F. LoBAsH ETAL 3,160,070

MICA UNDERCUTTER Filed oct. 25, 1962 7 Sheets-Sheet 5 INVEINTORJ! FLOYD l dens/4 MEW/N STRAUS Eo/WIRD fK/varJa/v wrnelww WY TToR/VEYJ Dec. 8, 1964 F. LQBASH ETAL MICA UNDERCUTTER Filed Oct. 25. 1962 '7 Sheets-Sheet 6 Dec. 8, 1964 F, I oBAsH ETAL 3,160,070

MICA UNDERCUTTER Filed oet. 25, 1962 7 sheets-sheet '7 N- KD INVENTOR!` FL o ra L OBA 6H M5L v//v JJTRA UB Eon/ARDI/(NurJa/v WWMM 3g ATTaR/vsrs MASTER COUNTER 3,156,437@ MESA UNDERCUTTER Floyd Lohash, Minneapolis, Melvin i. Straub, Hopkins, and Leonard 5. Knntson, Minneapolis, Minn., assignors to Essais Machine Corporation, hfiinneapolis, Minn., a corporation of lviinn-esota Filed Set. 25, i962, er. i To. 233,@15 8 lainis. (Cl. @Q -15.1)

This invention is a machine for undercutting the mica insulation between the copper segments of a commutator. lt is novel in that a photoelectric cell locates the commutator segments by registering a diiierence in the rate of light reflection as between mica and copper as the commutat-or is being indexed. The machine is also novel in having means for rendering the photoelectric cell ineffective during a portion of each searching period to minimize the chances of inaccurate signals being given by the photoelectric cell. The machine is further novel in that it does not cut the iirst time the photoelectric cell signals that mica has been found, which minimizes the errors in location of a correct starting position for the automatic cycle. The machine also incorporates simple adjustments for the cutting head and length of stroke aswell as the number or segments to be included in the cycle of the Vmachines operation which makes the machine very flexible in its application to armatures of different sizes.

Until rather recently most armature undercutting was done by hand principally by means of special tools designed to be eractly the width of the mica in a commutator. These tools are used simply by clamping the commutator carrying armature in a vise and pulling the manual tool down a mica slot until it has been undercut a desired depth. This method of undercutting is not only very slow but also somewhat inaccurate. `Since the hands are not completely steady in supporting the tool, sometimes it slips to one side or the other and mars the finish of the turned commutator.

@ne approach that has been made to the solution of this problem has been to provide jig guided power cutters. rthese machines have improved the situation, but are still relatively inaccurate. Location of a mica segment is still merely visual.

Attempts to provide automatic or semi-automatic machines for doing this mica undercutting have included both mechanical and electric-al mica searching devices. Electrical contacts or feelers riding on the commutator segments to distinguish between conducting copper and insulating mica is one structure that has been suggested. For a number of reasons, the exact nature of which is not material to this invention, these attempts have not been entirely successful. One of the major problems that is encountered in attempting to use this form of structure, as an example, that seems substantially insoluble without regard to a multitude of other diihculties is the diiliculty in adjusting the electrical contacts to recognize precisely the commutator segments of varying sizes. Also to permit these feelers to be in contact with the commutator and also keeping or moving them out of the way or" a cutter applied to the mica once located is difficult.

Accordingly it is the principal object of this invention to provide a novel mica undercutter.

It is a further object of this invention to provide a mica undercutting machine that requires no physical contact between the sensing means and the commutator itself in order to position and index the .commutator under the cutter.

A further object of this invention is to provide a mica undercutter that can be readily adapted to armatures of a wide range of sizes and number of segments.

It is another object of this invention to provide a mica United States Patent C) undercutter that minimizes errors in locating the starting i position for the automatic cycle of the undercutter.

It is another object of this invention to provide a mica undercutter that can be loaded and unloaded very` herent and apparent in the apparatus as described, pic-v tured and claimed.

To Vthe accomplishment of the foregoing andrelated' ends, this invention then comprises the features hereinafter fully described and particularly pointedV out in the claims, the followingdescription setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. v

. The invention will be described with reference to the drawings in which corresponding numerals refer to the same parts and in which: Y

FlGURE 1 is a front elevation of the machine with por- Vions or" the machine broken away to illustrate internal construction land with hidden parts illustrated with broken lines; v

FIGURE 2 is a top plan view of the device drawn to the same scale as FIGURE l and again with broken lines illustrating hidden parts; Y

FIGURE 3 is a plan view of the machine with the top panel and all the mechanism carried thereby and extending aoove it'removed; hidden portions of the device are show-n in broken lines and other portions of the machine are broken away to illustrate construction more fully;

FEGURE 4-is a partial longitudinal section, partial n side elevation of the machine taken from the left side as the machine is shown in FIGURE l; hidden parts are shown in broken lines;

FIGURE 5 is a detail of one of the cams driven by .the cam shaft of the machine and appearing on the left side thereof;

FIGURE 6 is a right hand side elevation with the covers of the machine removed and the machine considered as being shown in front elevation in FIGURE l;

.broken lines illustrate hidden parts;

slide vertically whenever the lock 15 (FIGURE 4) is released.

The slide assembly l2 carries the power cutter assembly i6 having a rotary cutter 17 on its shaft positioned adjacent to and vertically aligned with the spindle 18. A photoelectric cell unit i9 is supported by a sub-bracket 2i? that in turn is secured to a bracket 21 which is attached by any suitable means to slide l2. Thus,.the photoelectric cell il@ is carried with the cutter unit assembly and is moved vertically whenever thatunitis moved. Auxiliary bracketV 2% is also movable with respect to bracket 2l by any simple adjusting means such as the slot 22 which permits lateral movement of the photoelectric cell 19 relative to the spindle i8.. The photoelectric cell is not secured to shine vertically down on a commutator. While it will function so positioned, it has beenu found to work better if slanted at an angle of 10 plus or minus 5 with 10 being empirically determined to be the best angle.

Motor 24 drives the mechanism and'is supported on a conventional base 25 that is securely fastened to a cross Patented Dec. 8, 1964 two sprockets 28 and 29 are mounted. Sprocket 28 has a chain 30 reeved around it and engaging a sprocket 31V which, through a suitable direction changing device such as the gear box 32 (see FIGURE 3), provides means for driving the sprocket gear 34. A chain 35 is reeved around sprocket 34 and maintained with appropriate tension by the idler 36. Sprocket 34, by way of structure to be described hereinafter, drives spindle 18. Y

Sprocket 29 has a chain 37 reeved around it and a sprocket 38, whchis mounted to freely turn on cam shaft 39.. Cam shaft 39 issuitably supported by a bearing bracket 40 in FIGURE l, andsimilar bearing brackets that will appear and be described in connection with other drawings. At the right of bearing bracket 40 is a switch supporting bracket 41 which largely obscures the structure behind it that will be described in more detail in connection with other drawings. A switch panel `42 carries various controls necessary to start and control the sequence of operation of the machine.

Turning now .to FIGURE 2, motor cutter assembly 16 is seen actually supported by a slide mechanism 44 which is retained on bracket 12 by means of conventional ways 45. An adjustable link connector 46 interconnects slide 44 with the arm 47. Directly behind arm 47 is limit switch 48 the purpose and relationship to the rest of the structure of which will be explained hereinafter.

Spindle 18 is suitably supported in appropriate bearing blocks as at 49 and 59. Between these units is the pneumatic cylinder 51 which serves to actuate, pneumatically, the collet for clamping armature 52. The structure Y is seen in more detail in ,FIGURE 7.

Chain 35 and sprocket 54 are directly behind the bearing support 50. One portion of clutch 55 is secured to the sprocket 54 and this clutch element and the sprocket turn freely on the spindle shaft of spindle 1S except when the clutch is energized; then portion 55 lwhich is secured to the shaft of spindle 18 is rotated. At that time the spindle and the sprocket'54 rotate together, the sprocket driving the spindle shaft. Directly behind the clutch 55 is thebrake anchor 56 to which a portion 57 of the brake is secured. The other portion of the brake is secured to the shaft of the spindle 18v and when these two portions of the brake are engaged with each other in a braking.

4 when the brake is actuated, the shaft is held stationary to the plate 60. Again, as in the case of clutch S and brake 57 the clutch 62 and brake 64 operate in a mutually exelusive pattern.

manner, shaft 18 tends to be held stationary with the brake anchor 56. Electrically the clutch and the brake are interrelated so that only one of them is applied at any given instant.

Behind the brake is a special rotary joint 5S to which the air hose 59 connects; In this manner a stationary hose as at 59 can supply air to the rotating spindle 18 via the hollow center of the spindle shaft in' order. to actuate, pneumatcally, the collet. Panel` 42 appears` at the left in this view.

Turning now to FIGURE 3, the frame 10 isrep'resented in broken lines. Motor 24 and its associated speed reduction and direction changing gear box 27 appear centrally. Sprockets 28 and 29 together with their associated chains 30 and 37 are shown. Sprocket 34 is shown driven by chain 30 and via the direction changing box 32 drives sprocket 34. Idler 36 is also shown together with its adjusting structure.

Cam shaft 39 is shown supported in suitable bearings such as the one 40 near the left end of said cam shaft 39 and a similar bearing associated with brake anchor 69 near the right end of said cam shaft 39. Bearing 404 is supported on support plate 61. Cog 38 is seen engaged by chain 37 and the cog is also secured to a portion of clutch 62. The other portion of the clutch is keyed to the cam shaft 39. VThus, when the clutch is 1 energized, the chain 37 via cog 3S may drive the cam shaft.

Clutch 62 has a companion brake 64 secured to brake plate 60. A portion of the brake is secured to cam shaft 39 and the other portion anchored on the plate.v Thus Gn cam shaft 39 is box cam 65. A cam arm 65 is pivoted to plate 60 and has a cam follower engaged in boX cam 65. As the cam 65 rotates, the arm 66 is pivoted back and forth.

At the right hand end of cam shaft 39 is the cam 68 which alternately engages and disengages the switch 69 to help control the photoelectric cell unit as will be explained in greater detail below. A bracket 70 provides a support for switch 69.

At the left hand end of cam shaft 39 is the cam 71l which once in each revolution of the cam shaft engages and actuates switch 72 for purposes that will be made clear hereafter.

An adjustable linkage 74 is secured to cam 71 in a rotatable manner and also connected to ratchet crank 75. Ratchet crank 75 carries dog 76 that engages and operates the cog wheel 7'7. This cog wheel is suitably supported on support plate 61 and carries a removable cam plate 78. The cog 77 is also removable from its arbor support and these elements may be altered in order to adjust the machine for various operating conditions. A counter switch 79 is alternately engaged and disengaged by cam 73 for a purpose that will be explained in detail below.

In FIGURE 4 is shown clearly the structure of slide 44 and ways 45 by means of which motor assembly 16 is free to be slid back and forth in relation to an armature. Also clearly shown is the locking wheel 15 and the vertical adjustment wheel 14 by means of which bracket 12 may be raised and lowered to make vertical adjustments in the position of motor assembly 16. This provides adjustment for variations in commutator diameter.

The adjustment for variations in axial measurement of commutators for which the machine is desired to be adjusted appears alsoin FIGURE 4. Cam arm 66 will be seen to be pivoted to plate 60 in any suitable manner at point 80. The link 46 is pivotally secured to the cam arm 66. As cam arm 66 moves back and forth as its follower follows the path 31 of box earn 65 the link 46 is moved backwards and forwards a fixed amount. At 82 is seen the pivot of lever 47. Link 46 may be connected at various distances from pivot 82 by the simple expedient of the slot 84 and the clamping nut and bolt assembly 35.V This provides a means to achieve variation in the amount of pivoting imparted to lever 47. Obviously as arm 46 is moved closer to pivot 82, the upper end of arm 47 will be moved through a greater reciprocating arc since link 46 always moves a fixed amount. Likewise, if the nut and bolt assembly 85 is secured in slot 84 at its upper end or nearer to the linkage 46, the amount of movement imparted to the upper end of lever 47 is reduced. Here also, it appears clearly that linkage 46 is adjustable for length in order to compensate for the raising and lowering of bracket 12.

In FIGURE 5, plate 60 and a fragment of frame 10 are shown in relation to each other and the orientation of cam 68 with the switch 69 and switch bracket 70 appears clearly. A fragment of lever 47 also appears in order to orient all of the structure. j

In FIGURE 6 the nature of cam 71 appears Aclearly at the right having just passed switch '72. The link 74 connecting crank 75 obviously will pivot the end of the bell crank up and down as cam 71 rotates with the cam shaft 39. Dog 76 is shown engaging the teeth of cog 77 and moves one tooth for each revolution of the cam 71. Cam 78 will be seen to be a two lobe arrangement whereby counter switch 79 is actuated twice for each revolution of cog 77. This could just as well be a single lobe cam that operates counter switch 79 once for each revolution except that it is much easier to construct a cog 77 that will be easily operable for the `amount of throw available from cam 71, and link '74 when the teeth are the size of the gear 77 than they are if they must be made much larger than as shown. For extremely small armatures having only a few segments, it is dii`n`cult to make a single gear having teeth widely enough spaced to permit a single lobe to be rotated once with only a relatively few number of strokes of the link 74. The particular cog 77 and cam 78 are set up for a particular size of commutator having half as many segments as there are teeth in gear 77. Only one-half of a rotation of 'cog 77 measures a complete cycle of the machine for one commutator as it is shown here. Obviously, this cog and cam can be varied in order to provide for a variety in the number or segments in armatures of various sizes. For example, if an armature having exactly twice as many segments as there are teeth on cog 7'7 were to be undercut the cam 78 would be removed and a single lobe cam substituted therefor so that one entireV revolution of cog '77 would measure a complete cycle of the machine in undercutting the mica of the commutator.

Turning now to FIGURE 7, the arrangement of parts on the spindle from bearings i9 and Sil through the air hose 59 will be observed and the spindle is shown with the armature 52 grasped in collet S5. Collet 85 will be seen to have an external chamfer which substantially matches the internal chamfer of spindle 18. The collet 86 is threadably engaged in the collet receiving portion 83 of spindle 18 which in turn is secured to the piston S8. A pair of channel seals 89 and 9i) provide an airtight compartment within portion .71 of the spindle assembly and this creates a chamber 91 into I'which air may be introduced through the channel S7 via the rotating connector 5S and air hose 59 whenever a solenoid controlled air valve indicates that air should be applied at this point. The valve is conventional and hence neither shown nor described. The control for this air Valve is shown in the electrical diagram and its operation will be explained in connection with the electrical diagram. Whenever air is applied, however, the piston 83 moves to the right as shown in FIGURE 7 and in so doing it pulls collet 85 against the slanting shoulders of the internal chamfer of spindle 18. This causes the collet to squeeze down on the armature and grip it tightly. As soon as suiiicient air pressure has been applied to piston 88 to securely clamp the armature of the spindle, a pressure switch which is also conventional and therefore neither shown nor described except in the wiring diagram, initiates the operation of the balance of the machine by being actuated whenever pressure applied to the collet exceeds a predetermined value.

Turning now to` FIGURE 8, which is the electrical wiring diagram, the following units that appear'in the mechanical drawings l-7 may be seen identified by the same numbers as appears in those ligures. Holding the sheet with the ligure number at the bottom, Vthe counter 79 appears at the upper left and directly below it control panel 42. The motors 1o and 24 are directly below the control panel. At about the top center of the sheet is the photoelectric cell unit 19 and slightly to the left and below that may be seen the cam controlled photoelectric limit switch 69. Straight down near the bottom of the page, below photoelectric unit 19 is the 360 bump switch 72. Slightly to the right of center and near the top of the page appears the solenoid for the spindle brake 57 which is also identied by the abbreviation Br-S, meaning Brake Spindle in order to make it easier to follow the diagram without constantly referring back to see what the number 57 stands for. Likewise, below and slightly to the left of the spindle brake is the solenoid for the spindle clutch 55 identified as Cl-S. To the extreme right of the diagram may be seen 62, the clutch for the cam shaft, also identified as Cl-C, and below it the brake for the cam shaft 64, also identified as Br-C.

Only a few of the remaining elements showing the wiring diagram appear in the mechanical drawings and connected. Broken lines on relays represent interconnection of contacts mechanically but not electrically.

At the lefthand side of the drawing are the lines LI and LII. On the panel 42 are shown the master switch 9d which may be used to turn power on and oft from the y entire mechanism, the motor switch 91 which turns the motors on and oil? and also supplies power to mechanically operated limit switches to be described later, a cycle start switch 92 and a cycle interrupt switch 94. All of these switches have also been labelled with either a name or abbreviation of their function so that it will be easier to follow the discussion of the wiring diagram without constant reference back to the specitication to identify the various units by number. This procedure will be fol'- Vlowed throughout the description of the wiring diagram. For example, the cycle start switch is labelled CSt and the cycle interrupt switch is labelled CSL At 9S appears a pilot light which merely indicates that power is being applied to the motors and other circuits connected in parallel 4to the motor circuit.

From lines LI are a series of branch lines beginning at the left and following down and around to the right bearing the numbers vserially 96, 97, 98, 99, 11N), 161, 1132, 1114, 19S, 1%, 107, 108 and 109 which are leads connecting various units to Ll. T hese lines remain constantly connected to LI.

From master switch 90, a lead 1ll9 leads to a junction point from which lead 114i extends down -to the photoelectric cell unit 19, labelled PE. A lead 111 extends therefrom to a second junction point from which a lead 112 extends down to and is secured to terminal g of the' unit 114 Vwhich is the armature rotation rectiier and labelled ARR. A lead 115 continues on across and connects a terminal b .of elementlll also labelled CRR for the cam rotation rectifier.

The internal mechanism of these rectiliers is not illustrated as they are standard units purchased on the market and only the circuit interconnecting them with the balance of the circuit which is unique with this machne will be described.

From the master switch to the motor switch a lead 117 extends so that whenever lthe master switch is closed, the motor switch is supplied-with a source of energy from LH. From the other terminal of the motor switch a lead 118 extends to pilot light 95, thereby completing the circuit lfor that unit. A lead 119 extends down from the motor switch to the motor 16 and another :lead 129 extends to motor 24. A lead 121 extends therefrom to the 360 bumpswitch 72 thereby connecting oneterminal of that switch with a source of energy from LII whenever the motor switch is closed. From the same terminal of hump switch 72 to which lead 121 connects, a lead 122 extends to limit switch 43 which is the switch actuated by the cutting arm and herein referred to as cutting limit or CL. A jumper lead 124l connects one side of the motor switch also to one terminal of switch 92, the cycle startswitch also labelled CSt. Another lead 125 connects to this same terminal of the cycle start switch and one side of switch 79, also known as the counter'. A lead 126 Vextends to the cycle interrupt switch 94.

Lead 127 connects the other terminal of the cycle` interrupt switch with one of the relay terminals Ria of relay designated R1. Lead 113 connects thev `terminal d of the photoelectric unitv to the power terminal B of the armature rotation rectifier 114 while lead 123 connects the power lead B of unit`114 with one terminal of relay points R441. As relay R1 .is deenergized and remains spring loaded in the position shown in the drawings when deenergized and except when a microswitch has Vbeen found, relay terminals R1a will he closed at least during the early stages of operation.

All of the leads designated so far are shown in lines substantially heavier than the balance of the leads. The purpose of this is to identify the leads which substantially always have power applied to them either constantly when the machine is connected and turned on with the exception of special circumstances specifically noted.

A lead 128 connects the otherof the terminals Ria to one switch terminal of theV set RZC on the relay designated R2 at about the center of the diagram. From bump switch 72 a lead 129 extends up and joins to the same terminal of R26 as lead 12S connects. From the other terminal of relay contacts R26 a lead 136 extends to one terminal of the pressure switch 131 also labelled P. This pressure switch is a unit that responds to air pressure to close the switch when air pressure exceeds a given value. lt is a commercial unit and not described further. f From this same terminal a lead 132 extends to the .unit 134 which is the coil of the solenoid valve that applies air pressure to the collet. When this valve opens, air pressure is applied to make the collet grip an armature shaft. As long as the collet is moving to clamp on an armature shaft, air pressure does not build up. When it stops moving and oers `resistance to applied air pressure, air pressure builds up sufciently to cause pressure switch 131 to close its electrical contacts. 135 connects the same terminal of the pressure switch to the opposite terminal of the cycle start switch 92 on panel 42. From the opposite .side of pressure switch 131, a lead 136 extends to a junction point from which lines 13'7, 138,139 and 141B extend to various units in the following consecutive order: the contacts Rltlc of relay R11), the contacts R1`c of relay R1, the contacts R11d of relay R11, and to a second junction point from which the leads 141 and 142. extend. Lead 141 connects to one of the coil terminals of relay R2 while lead 142 extends to the contacts R3c of relay R3 at the righthand side of the diagram. On relay R isa jumper lead 144 extending from the other of terminals R195* to one side of the coil'for relay R16', relay R11 has a similar jumper 145. On relay R3 is another similar jumper 146. All of the wire numbers between and including leadsl 12S and 146 are made somewhat lighter than the Vheaviest leads but somewhat darker' th-an the remaining leads in the drawing. The reason for this is that these leads are connected to power more or less constantly during a normal cycle operation of the machine and will he referred to frequently hence are made darker to be more easily identified.

The lead147 connects one side of the relay terminals R1b to one side of the relay` terminals R105 while a jumper designated 148 interconnects the two terminals of the relay point R1!) and Rlc. A lead 149 connects the other of relay terminals R10 to the relay terminals R111). A lead 15G connects oneterminal of the coil for relay R1 `with the relay switch terminal designated c on photoelectric unit 19v while the other terminal of relay coil R1 is connected by lead 151 to the terminal d of the unit 114, the armature rotation rectifier.

Turning now to the terminals of the relay R16 and the relay R11, a lead 152 connects one sideof the relay terminals R191) to one terminal of the coil of relay R11. A lead 153 interconnects one of relay terminals Rla to one of relay terminals R11a while a lead 154 connects the other of these two pairs of terminals Rliia and R11a together. These sets of terminals are therefore connected in parallel to each other. From the same terminal of A line AP o R11a alead 153 is connected, a lead designated 155 extends to one terminal of the cam operated switch 69. From the oppositev side of this cam switch, a lead 156 extends to the terminal marked H1 on the photoelectric unit 19. The terminal of this same unit marked H2 is connected by a lead 157 to one of terminals R211 of relay R2. When H1 and H2 are connected together, the photoelectric unit is given the signal that it should hunt for a mica strip. A lead 153 interconnects the other of the terminals of R222 to the same side of terminals Rlla that lead 154 is connected to. A jumper designated 159 connects one side of points R: with relay points Rllc.

A lead 160 extends between one terminal of the coil for relay R10 and one side of the points R110 for relay R11. Lead 161 connects one side of the points R111? with one side of the relay R3, the same one to which lead 146 is connected. v

Turning now to the balance of the connections on the photoelcctric cell, a jumper lead 162 interconnects the terminals f and d which are two of the relay contacts of the relay actuated hy the photoelectric cell and shown herein as an integral part of that unit, for purposes of convenience and understanding. A broken line interconnects the switch blades of these relay points indicating n that they are operated simultaneously. The one having terminals cd is normally closed and the onehaving terminals ef is normally open. When the terminals H1 and H2 are connected and the photoelectric cell detects a change in the rate of light reflection which in this application is the distinction between the copper segments of the commutator and the mica insulating thereof, the relay coil is energized by an internal circuit of no patentable significance here, and the position of the knife blades for the `relay having terminals cd is open while that for the terminals ef is closed.Y

Connected also to the terminal c on photoelectric unit at the same point where lead is connected, is a lead 164 which extends to the terminals R40 of the relay R4. From the terminal e of the photoelectric unit 19 a lead 165 extends to the terminals R4b of relay-R4 To the relay R2 and to complete the connections thereof, the points R24.y have a lead 166 that Aextends to the terminal a on unit 114 the armature `rotation rectifier. The other side of this same set of points has a lead 167 which extends to the other lside of the relay switch terminals R4H from that to which lead 123 is connected'.

The relay R4 has a lead connected tothe opposite one ofthe relay terminals Rlcrfrom that which '164 is connected and this second lead connected to R40 is 163. It extends over toand is joined with a lead-169 which interconnects the clutch for the spindle 55 with the terminal c on the armature rotation rectier unit 114. The other side of the solenoid for the spindle clutch 55 is connected by a lead 17h to lead 151 which inturn connects to terminal. d of the rectiiier Lfor armature rotation. The brake spindle Y5'7 is connected hy a lead 171 to terminal e of the rectifier for armature rotation while its other terminal is connected by lead 172 to the terminalf of that same rectifier. Between the cutting limit switch 48 and one terminal of the coil for relay R4 extends a lead vBetween the relay points RSb and terminale of the cam shaft rotation rectiier 116 extends a lead 175. The other side of this same set of points is connected by a lead 176 to the cam shaft brake member 64, which brake terminal is also connected by a lead 177 to e of the cam rotation rectifier. From d on the cam rotation rectifier 116 a lead 178 extends to one of the terminals of the relay switch R3 designated as RSa. From the opposite side of those same terminals a lead 179 extends to one terminal of the cam shaft clutch 62. A lead 189 interconnects the same terminal or the cam shaft clutch withA terminal f on the rectifier while a lead 131 interconnects the other side of the cam shaft clutch 62 with terminal g. The terminal of the cam shaft clutch which is connected -the circuit for this coil.

Q to lead 181 is interconnected by a jumper 182 with the corresponding side of the brake for the cam shaft 64 electrically speaking.

Operation '85 of appropriate size is selected and inserted in spindle 18. With the machine thus readied for operation, an

armature 52 is inserted in the collet, the machine isv turned on. Master switch 9G and motor switch 91 are both turned on which sets the motors inl operation and supplies power to the photoelectric unit and the two rectiers. When everything is set as described above, the cycle start switch 92 may be engaged.

With the depressing of the cycle start switch 92, a circuit is completed between lead 124 which has been con- 'nected to line LII by the closing of the master and motor switches and line 135 that connects to the pressure switch 131. v'V'ia'the lead 132 energy is supplied to solenoid 134 for the collet air valve. Upon the collet air valve being Opened, air is supplied to the collet which causes it to close on the armature shaft and instantly upon doing so, air pressure is quickly built up to activate pressure switch Upon the closing of pressure switch 131, a circuit is completed via leads 136, 140 and 141 to the coil of relay R2. This activates relay R2 whereupon a holding circuit is established for relay R2. At other times this holding circuit may be completed by the closing of the relay points RZC when R2 is energized and power applied via leads 124, 125, counter switch 79, lead 126, the cycle interrupt switch 94 (which is normally closed), lead 127 through the points R1a that are closed at lthis stage through the lead 128 to one terminal of relay points R2C. This holding circuit comprises a circuit from line LII through the master and motor switches and lead 119, lead 12?, lead 121, through the 360 bump switch 72 (which is normally closed at this stage), and lead 129 to the terminals RZC; From the lother side of this set of terminals RZC, lead 130 extends back to the same side of pressure switch 131 asV temporary power is provided by lead 135 from the cycle start switch. 7 Since the pressure switch 131 is closed, continuing power is applied via leads 136, 14u. and 141 to the coiltRZ. Leads lil@ and ltltl join the other side of coil R2 `to line Ll'and complete gized throughout a cycle unless interrupted by some abnormal situation or by purposely opening the cycle interrupt'switch 9d simultaneously with the actuation lof the 369 bump switch '72 which occurs once for each revolution of the cam shaft.

At this time it should be pointed out also that with the closing of the master switch, a circuit is provided for power to armature rotation rectier and upon this happening,` with relay R4 in its unenergized position, power is provided via lead 113 through the photoelectric relay switch terminal Cd, lead lea' to relay points R40 and through these closed points via lead li-o to leads 163 and 169 to the clutch for the spindle 55 which isthen energized by the continuation of current tlow through lead 17)v and lead 151 back to terminal dof the armature rotation rectilier. Upon energizing clutch S, the power from motor 24 is applied to spindle 1S and it begins to rotate. At the same time power is not applied at ter- Y minal a of the armature rotation rectifier since the relay terminals Rla stand open. Furthermore, relay points Cf Thus relay R2 remains enerfor the photoelectric unit 19 stand open so tht power cannot be derived via the lead 113 and jumper 162, lead 165, the relay points R45 and the jumper connecting the y relay points Rdc and'Rlb and lead 167 via the relay R2 For this reason, Y spindle brake 57 is not energized and therefore the spindle and by lead back to terminal a.

is free to rotate. y Upon closing of `relay R2 .as described above, a path is provided from H1 via lead 156 through the photoelec-V tric cam switch e9, lead 155, jumper lead 153, relay points Rlila, leadV 154, lead 15% and lead 157 back to H2.

Since the photoelectric cell 19 hunts or searches `for va change in rate of rellected light whenever the terminals H1 and H2 are connected, it begins to serve this func Upon the actuation of photoelectric cell relay, the Y power that previously was applied to the coil Vof relay R1 is no longer applied. As ya result, relay R1 under spring tension reverts to the position shown in the wiring diagram and in so doing a path is completed fromthe pressure switch 1.11 via lead 136, lead 138 through the points Rlc of relay R1via lead M9, jumper 159, the closed relay points R11C ot relay R11 rand by jumper 160 to the coil of relay R19. This path of :current flow causes the relay R1@ to be activated and in so doing the positions of .all of the points of relay R13 are reversed from thatV shown in the diagram. As a result, the'relay points R10C are closed and a continuing or holding circuit is now pro-v power by the activating circuit. As long as pressure switch 131 remains energized and supplied with power, therefore, there is a complete circuit to hold relay R10 in `its energized position. v f

Upon relay 19C being energized, fthe relay points 10a through which the circuit between H1 and'HZ was completed are opened and the circuit betweeny H1 audfHZ broken. A As soon as this happens, the circuit energizing the photoelectric cell relay is deenergized and the points cd are again closed while the points ef are opened. The armature immediately begins rotating again as described above and relay R1 is again energized.

Energizing the relay R1 closes the points Rlb and a circuit is then completed from the pressure switch through line 136, line 138, jumper 148, relay points Rlb, lead 147 through the relay points Rlillnlead 152 Vto the'coil of relay R11. vThe other side of the relay coil R11` is connected by line 192 and 10i) to line- Ll hence the relay coil is energized and all of the points are moved to the opposite position from that shown'in the drawing.

Relay points R11c then complete a circuit between line 13.9 which is suppliedV with energyv via the pressure switch 131 and through jumper 145, a holding circuit is established through the coil relay R11. Thereafter, as long as energy is supplied through'the pressure switch, the relayrRll remains in the energized position as .does the relay R16. Relay points R11a lare closed 'which provides analternate circuit between H1 and H2 of the photoelectric unit 19. This circuit includes line 157, the points R2b, the points R11a,`lead 155, the photoelectriccam driven limit switch 69 andlead 156. As soon as the1circuit between H1 and H2 is completed, the photoelectric cell again begins to search for a change in the Ieecting ability of the surface of the commutator. Upon they photoelectric cell finding mica, such a change in reflected light rate occurs and its relay is again energized. Points cd are opened and the points ef closed. This again causes the clutch for the spindle 55 to be deenergized andthe brake applied, thereby stopping rotation of the yarmature with a mica segment aligned under the cutting head.

The reason for the system beingv set up s'o'thlat the 1l rst time photoelectric cell 19 iinds a mica insulator it does Vnot cause the machine to react for its cutting phase is to prevent false starts. It was discovered that many times a commutator segment will have been marked in some manner, as by ra tool scratch or the like, which will change the light reiiecting effect of the surface of the copper segment and perhaps cause the photoelect'ric cell 19 to signal that it had found mica when in fact it had not. By skipping the first such possible signal and waiting until the second, it was discovered that most ofthe false signals could be avoided with respectV to initiating a cutting cycle. In this manner, the machine is almost certain to undercut the iirst time on mica. By reason of structure thatwill be described later, the possibility of error after making sure that the machine starts on a mica portion is greatly reduced.

As soon as relay R11 is energized, and relay R1 is deenergized by the movement of the photoelectric cell relay from the lead 138 which provides power via the pressure switch and lead 136, the relay points Ric, now closed, provide power via the lead 149 through the relay points Rllb and lead 161 to the relay R3 which energizes thatcoil since the lead 165 is connected to the line LI. Again, once the line closes, a circuit is provided via lines 136, 140 `and 142 to the points R3c and via the jumper 146 provides a holding circuit which causes the relay R3 to remain in the energized position as long as the automatic cycle continues. Upon this action, the brake circuit via points R3!) is interrupted while the clutch circuit via points R3a is completed. vThus, theY brake that has been holding the cam shaft stationary is released and the clutchis energized, causing the cam shaft to be ro- `tated by motor 24.

Upon the cam shaft belng rotated, the .cams secured thereto of course are rotated and including box cam 65 which causes the arm 47 to begin moving forward on the forward cutting stroke. As this happens, the spring loaded closed cutting limit switch 48 is released and its spring forces it closed thereby completing a circuit via the motor power leads, the lead 121, the -lead 122 and the lead 174 to actuate the coil R4 which is connected via the line 16 to the line L1. As soon as this relay is actuated, it rearranges the circuits for the spindle clutch and the spindle brake so that the latter remains applied and the former is detached regardless of the condition of the photoelectric relay which earlier interrupted the clutch circuit and applied the brake circuit. This guarantees that fthe armature will continue to stand during the cutting phase.

A the stroke of the cutting unit continues with the rotation of lcam shaft 39, the cam shaft is also driving cam 68 which in turn opens the photoelectric cam limit switch 69 thereby interrupting the circuit between H1 and H2. Y

The photoelectric relay again drops back to the position illustrated inthe wiring diagram thereby making it possible for the spindle clutch and brake to be reactivated in thereverse pattern to that which they are being held at that instant bythe energized relay R4 as soon as relay R4 is deenergized. This `also causes relay R1 to be actuated.

As arm 47 approaches the completion of its rearward stroke, however, it engages and reopens to the position shown in the wiring diagram, the cutting limit switch 4S. As soon as this is done relay R4 is deenergized, and under spring tension reverts to the condition shown in the wiring diagram. As soon as that happens, the brake and clutch for 4the spindle are under the control of the photoelectric relay. Since it has been deenergized by the opening of the photoelectric cell cam switch 69, the brake immediately releases and the clutch is applied, producing rotation of the spindle. After a few degrees of rotation which may be adjusted by proper locationfof the cam 68 on shaft 39, the photoelectric cell cam limit 69 is again closed and instantly the circuit between H1 and H2is .reestablished which starts the photoelectric unit searching for mica or more specifically for a change in the rateof reflected light being applied to the commutator. In most instances, of course, this will be the difference bewteen copper and mica. The reason for using the photoelectric cam switch 69 is to minimize the period of time when the photoelectric `unit is searching for a light difference so that it will be less likely in the course of the complete cycle to be fooled by imperfections of various sorts in the surface of the copper which might change the rate of reflected light suiiciently to cause it to signal as though it had found mica. Thereafter the photoelectric cell alternately stops and starts the spindle lining up mica segments under the cutter while the cam shaft continues to rotate under the holding action of relay R3 unless for any reason the machine completes one revolution of the cam shaft without iinding mica.

In the event the photoelectric relay fails to discover a mica segment during one complete revolution of cam shaft 39, the relay of the photcelectric cell remains in the position shown in the diagram and as a result, the coil for relay R1V is energized. This being the case, the circuit between leads 127 and 128is interrupted at points Rla. For this reason, no power is applied to the holding coil of relay R2 via lead 128. If this condition should continue to the end of a rotation of the cam shaft, without a mica segment being found, the 360 bump switch 72 will be opened by theY cam shaft rotation and as a result power will be cut oif from lead 129 also. If this should occur, power to pressure switch 131 will be interrupted since line 130 will have no power from either of its two potential sources of power. For this reason, all ofthe circuits that are supplied with energy via the pressure switch 131 will be interrupted and this includes the circuits for coil R2, R3, R10 and R11. In short, the machine will return `to the condition it was in before the cycle start switch was pushed, except that the counterswitch will not be in the position it should be for the beginning of the cycle. Under these circumstances, the operator will investigate the commutator to discover what the problem is. Having once determined what the problern is, he can reset the commutator in the spindle in such a manner that he can restart the automatic cycle and cause the machine to complete undercutting the mica of the armature. Stopping the cycle can be effected also by pushing the cycle interrupt switch 94.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from Ythe spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

What is claimed is:

1. A commutator mica undercutting machine comprising: a frame, a commutator holding means rotatably supported on said frame, means for rotating said commutator holding means a releasable brake associated with said commutator holding means for stopping rotation, a clutch alternately operable with said brake for engaging said rotatingV means and said commutator holding means when said brake is released, a photoelectric unit responsive to changes in rate of light retiection secured to said frame above said commutator holding means, said photoelectric unit being canted with its top farther from a vertical projection of said commutator holding means than its bottom and its center line forming an angle ofl 10 with a vertical line, a relay controlled by said photoelectric unit, said relay controlling thek application of said brake and release of said clutch, a cutting mechanism movably secured to said frame adjacent to said armature holding erating said switch to render said photoelectric unit search signal circuit inoperative during a portion of each period of rotation of said commutator holding device.

2. The structure of claim l in which said means for axially moving said cutting mechanism includes a cam shaft rotatably secured to said frame, a box cam secured to said cam shaft, a cam arm having a cam follower thereon engaged in said box cam, the other end of said cam arm being pivoted to said frame, a lever pivoted to said frame and interconnected with said cutting mechanisrn, and a link interconnecting said arm and said lever, said link being secured to one of said cam arm and lever by a releasable clamping means whereby said link may be moved to and from the pivot point of one of said cam arm and lever to adjust the length of axial movement of said cutting mechanism.

3. The structure of claim 2 in which a cutting limit switch is secured to said frame in alignment with said cam arm, said cam engaging said limit switch opening it and holding it open near the rearmost position of said cam arm, a relay controlled by said cutting limit switch, said relay interconnected with said photoelectric unit, brake and clutch, said limit switch, photoelectric unit and relay together controlling the release of said brake and engagement of said clutch.

4. A commutator mica undercutting machine comprising: a frame, a commutator holding means rotatably supported on said frame, means for rotating said commutator holding means, a releasable brake associated with said commutator holding means for stopping rotation, a clutch alternately operable with said brake for engaging said rotating means and said commutator holding means when said brake is released, a photoelectric unit responsive to changes in rate of light reflection secured to said frame above said commutator holding means, a relay controlled by said photoelectric unit, said relay controlling the application of said brake and release of said clutch, a cutting mechanism movably secured to said frame adjacent to said armature holding means, means secured to said cutting mechanism and said frame for moving said cutting means axially with respect to a supported commutator when said brake means is applied, switch means connected electrically into the photoelectric unit search signal circuit, and a cam operating said switch to render said photoelectric unit search signal circuit inoperative during a portion of each period of rotation of said armature holding device, said means for axially moving said armature holding device includes an arm, a cutting limit switch secured to said frame near said arm, said cutting limit switch engaged, opened and held open by said arm in its cutting means withdrawing position, a relay controlled by said cutting limit switch, said relay interconnected with said photoelectric unit, brake and clutch whereby said cutting limit switch, said relay and said photoelectric unit together control the release of said brake and the engagement of said clutch.

5. A mica undercutter comprising a frame, a spindle rotatably secured to said frame and alternately rotatable and stationary, a mica cutting mechanism movably secured to said frame adjacent to said spindle, a cam shaft and linkage means for driving and cutting means reciprocally,

means secured to said frame and said spindle for alter` nately rotating it and holding it stationary, a photoelectric unit aimed at a commutator supported by said spindle and sensitive to the rate a which light is reflected from a commutator supported by saidspindle, said photoelectric cell when sensing a significant change in the rate of reflected light from a commutator closing a relay that initiates the stopping of said spindle and the initiating of movement of said mica undercutting mechanism, a relay means secured to said control circuit for cancelling the irst of said signals given by said photoelectric unit in any one cycle of operation of said machine, and a relay that initiates the stopping of said spindle and the beginning of a mica undercutting mechanism operation upon the second of such signals from said photoelectric unit.

6. The mica undercutting device of claim 5 in which a limit switch is connected into the Search signal circuit of said photoelectric unit, said limit switch mechanically operated by said cam shaft to render said photoelectric unit insensitive during a portion of each period of rotation of said spindle.

7. The mica undercutter of claim 6 in which a limit switch is positioned adjacent said cutting driving means linkage for rendering said spindle rotating means unconditionally inoperative whenever said mica undercutting mechanism is being actuated.

8. The mica undercutter of claim 5 in which a limit switch is positioned adjacent said cutting driving means linkage for rendering said spindle rotating means unconditionally inoperative whenever said mica undercutting mechanism is being actuated.

References Cited in the file of this patent UNITED STATES PATENTS 1,879,549 Sethman Sept. 27, 1932 2,090,151 Poole Aug. 17, 1937 2,180,771 Poole Nov. 21,- 1939 2,318,856 Hoiman May 11, 1943 2,380,859 Marsilius July 31, 1945 2,520,514 Spector Aug. 29, 1950 2,718,177 Karmann Sept. 20, 1955 2,882,420 Koulicovitch Apr. 14, 1959 2,894,178 Chesebrough et al. July 7, 1959 2,999,938 Hann et al. Sept. 12, 1961 3,004,166 Greene Oct. 10, 1961 3,005,916 Lentze Oct. 24, 1961' 3008.382 Hawley et al NOV. 14. 1961 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent' Ne.. 3Y1eo,o7o. December e,1 1964 Floyd Lobash et alu It s hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column ll, line 50, for "A" read As column l2y line lY for "bewteen" read between column 'l4 line ll, for "a"Y first occurrencev read at line 42V for Signed and sealed this 20th da-y'of April 1965.

(SEAL) Attest:

ERNEST W. SWIDER O EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A COMMUTATOR MICA UNDERCUTTING MACHINE COMPRISING: A FRAME, A COMMUTATOR HOLDING MEANS ROTATABLY SUPPORTED ON SAID FRAME, MEANS FOR ROTATING SAID COMMUTATOR HOLDING MEANS A RELEASABLE BRAKE ASSOCIATED WITH SAID COMMUTATOR HOLDING MEANS FOR STOPPING ROTATION, A CLUTCH ALTERNATELY OPERABLE WITH SAID BRAKE FOR ENGAGING SAID ROTATING MEANS AND SAID COMMUTATOR HOLDING MEANS WHEN SAID BRAKE IS RELEASED, A PHOTOELECTRIC UNIT RESPONSIVE TO CHANGES IN RATE OF LIGHT REFLECTION SECURED TO SAID FRAME ABOVE SAID COMMUTATOR HOLDING MEANS, SAID PHOTOELECTRIC UNIT BEING CANTED WITH ITS TOP FARTHER FROM A VERTICAL PROJECTION OF SAID COMMUTATOR HOLDING MEANS THAN ITS BOTTOM AND ITS CENTER LINE FORMING AN ANGLE OF 10* WITH A VERTICAL LINE, A RELAY CONTROLLED BY SAID PHOTOELECTRIC UNIT, SAID RELAY CONTROLLING THE APPLICATION OF SAID BRAKE AND RELEASE OF SAID CLUTCH, A CUTTING MECHANISM MOVABLY SECURED TO SAID FRAME ADJACENT TO SAID ARMATURE HOLDING MEANS, MEANS SECURED TO SAID CUTTING MECHANISM AND SAID FRAME FOR MOVING SAID CUTTING MEANS AXIALLY WITH RESPECT TO A SUPPORTED COMMUTATOR WHEN SAID BRAKE MEANS IS APPLIED, SWITCH MEANS CONNECTED ELECTRICALLY INTO THE PHOTOELECTRIC UNIT SEARCH SIGNAL CIRCUIT AND A CAM MECHANICALLY LINKED TO SAID CUTTER MOVING MEANS AND OPERATING SAID SWITCH TO RENDER SAID PHOTOELECTRIC UNIT SEARCH SIGNAL CIRCUIT INOPERATIVE DURING A PORTION OF EACH PERIOD OF ROTATION OF SAID COMMUTATOR HOLDING DEVICE. 